Method and arrangement for manufacturing a laminated structure

Abstract

A method for manufacturing a laminated structure for use in an absorbent article such as a diaper, a sanitary napkin, a panty liner, an incontinence pad or similar and being defined by a plurality of material layers comprising at least a first layer which is liquid-permeable, a second layer constituting an absorbent core and a third layer, each of the layers being formed of a material having a certain pore radius. The method includes bonding together the material layers by means of at least two ultrasonic welding steps; and providing an ultrasonic welding pattern for each of the welding steps, each of the welding patterns being defined by a plurality of bonding sites. The method includes providing the welding steps for forming generally the entire absorbent article; and selecting the welding patterns in a manner so that at least the entire laminated structure has a multiple pore radius.

The invention claimed is: 
     
       1. A method for manufacturing a laminated structure for use in an absorbent article, the laminated structure being defined by a plurality of material layers comprising at least a first layer which is liquid-permeable, a second layer constituting an absorbent core and a third layer, each of said layers being formed of a material having a certain pore radius, said method comprising:
 a first welding step in which said third layer and said second layer are bonded together using ultrasonic welding to create a first welding pattern of bonding sites; and 
 a second welding step in which the bonded third and second layers are bonded together with said first layer using ultrasonic welding to create a second welding pattern of bonding sites; 
 wherein in the resulting laminated structure of the three layers, the first welding pattern of bonding sites is present only in the second and third layers, and the second welding pattern of bonding sites is present in all three layers, so as to provide a pore gradient extending through the three layers. 
 
     
     
       2. The method according to according to  claim 1 , wherein said third layer is a liquid-impermeable backsheet. 
     
     
       3. The method according to  claim 1 , wherein the absorbent article is a diaper, a sanitary napkin, a panty liner, or an incontinence pad. 
     
     
       4. The method according to  claim 1 , wherein the pore radius of the first layer is larger than the pore radii of the second and third layers. 
     
     
       5. The method according to  claim 1 , wherein in the resulting laminated structure, the first layer has fewer bonding sites than the second and third layers. 
     
     
       6. A method for manufacturing a laminated structure for use in an absorbent article, the laminated structure being defined by a plurality of material layers comprising at least a first layer which is liquid-permeable, a second layer constituting an absorbent core and a third layer, each of said layers being formed of a material having a certain pore radius, said method comprising:
 bonding together said material layers by means of at least two ultrasonic welding steps; and 
 providing an ultrasonic welding pattern for each of said welding steps, each of said welding patterns being defined by a plurality of bonding sites; 
 wherein it comprises: 
 providing said welding steps for forming the entire absorbent article; 
 selecting said welding patterns in a manner so that the entire laminated structure has a multiple pore radius; 
 and wherein said welding steps comprise at least, and in the following sequence: 
 a first welding step in which said third layer and said second layer are bonded together; and 
 a second welding step in which the bonded third and second layers are bonded together with said first layer; 
 wherein said welding steps are carried out using a first layer being formed from a material having a pore radius which is equal to or greater than the pore radius of the second layer and the third layer, and also using a second layer being formed from a material having a pore radius which is equal to or greater than the pore radius of the third layer. 
 
     
     
       7. An arrangement for manufacturing a laminated structure for use in an absorbent article, the laminated structure including at least a first layer which is liquid-permeable, a second layer constituting an absorbent core and a third layer, each of said layers being formed of a material having a certain pore radius, said arrangement comprising:
 a first ultrasonic welding device arranged for bonding together said second and third material layers, said first ultrasonic welding device constructed so as to impart a first bonding pattern on said second and third material layers; 
 a second ultrasonic welding device arranged for bonding together all three material layers, said second ultrasonic welding device constructed so as to impart a second bonding pattern on all three material layers, wherein the second bonding pattern is different than the first bonding pattern; 
 wherein said ultrasonic welding devices are arranged so as to provide a pore gradient extending through the three layers. 
 
     
     
       8. The arrangement to  claim 7 , wherein the absorbent article is a diaper, a sanitary napkin, a panty liner, or an incontinence pad. 
     
     
       9. A laminated structure for use in an absorbent article, the laminated structure comprising:
 at least a first material layer which is liquid-permeable, 
 a second material layer constituting an absorbent core, and 
 a third material layer, 
 each of said layers being formed of a material having a certain pore radius, said laminated structure being formed by bonding said three material layers together by at least two ultrasonic welding steps providing a different ultrasonic welding pattern for each of said welding steps, 
 each of said welding patterns being defined by a plurality of bonding sites wherein the laminated structure is formed through said welding steps; and 
 wherein said material layers and welding patterns are selected in a manner so that the entire laminated structure has a graduated pore radius extending through the three layers; and 
 said third layer and said second layer are bonded together with a first ultrasonic welding pattern; and the bonded third and second layers are bonded together with said first layer with a second ultrasonic welding pattern. 
 
     
     
       10. The laminated structure according to  claim 9 , wherein said third layer is a liquid-impermeable backsheet. 
     
     
       11. The laminated structure according to  claim 9 , wherein the laminated structure is formed by said welding steps comprising at least, and in the following sequence: a first welding step in which said third layer and said second layer are bonded together; and a second welding step in which the bonded third and second layers are bonded together with said first layer. 
     
     
       12. The laminated structure according to  claim 9 , wherein said welding steps are carried out using a first layer being formed from a material having a pore radius which is equal to or greater than the pore radius of the second layer and the third layer, and also using a second layer being formed from a material having a pore radius which is equal to or greater than the pore radius of the third layer. 
     
     
       13. The laminated structure according to  claim 9 , wherein the laminated structure comprises two nonwoven layers and two absorbent cores. 
     
     
       14. The laminated structure according to  claim 9 , wherein the laminated structure comprises a nonwoven layer, two absorbent cores and a backsheet. 
     
     
       15. The laminated structure to  claim 9 , wherein the absorbent article is a diaper, a sanitary napkin, a panty liner, or an incontinence pad. 
     
     
       16. An absorbent product comprising a laminated structure according to  claim 9 . 
     
     
       17. An absorbent product comprising a laminated structure according to  claim 10 . 
     
     
       18. An absorbent product comprising a laminated structure according to  claim 11 . 
     
     
       19. An absorbent product comprising a laminated structure according to  claim 12 .